1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3 * PARISC Architecture-dependent parts of process handling
4 * based on the work for i386
5 *
6 * Copyright (C) 1999-2003 Matthew Wilcox <willy at parisc-linux.org>
7 * Copyright (C) 2000 Martin K Petersen <mkp at mkp.net>
8 * Copyright (C) 2000 John Marvin <jsm at parisc-linux.org>
9 * Copyright (C) 2000 David Huggins-Daines <dhd with pobox.org>
10 * Copyright (C) 2000-2003 Paul Bame <bame at parisc-linux.org>
11 * Copyright (C) 2000 Philipp Rumpf <prumpf with tux.org>
12 * Copyright (C) 2000 David Kennedy <dkennedy with linuxcare.com>
13 * Copyright (C) 2000 Richard Hirst <rhirst with parisc-linux.org>
14 * Copyright (C) 2000 Grant Grundler <grundler with parisc-linux.org>
15 * Copyright (C) 2001 Alan Modra <amodra at parisc-linux.org>
16 * Copyright (C) 2001-2002 Ryan Bradetich <rbrad at parisc-linux.org>
17 * Copyright (C) 2001-2014 Helge Deller <deller@gmx.de>
18 * Copyright (C) 2002 Randolph Chung <tausq with parisc-linux.org>
19 */
20
21 #include <stdarg.h>
22
23 #include <linux/elf.h>
24 #include <linux/errno.h>
25 #include <linux/kernel.h>
26 #include <linux/mm.h>
27 #include <linux/fs.h>
28 #include <linux/cpu.h>
29 #include <linux/module.h>
30 #include <linux/personality.h>
31 #include <linux/ptrace.h>
32 #include <linux/sched.h>
33 #include <linux/sched/debug.h>
34 #include <linux/sched/task.h>
35 #include <linux/sched/task_stack.h>
36 #include <linux/slab.h>
37 #include <linux/stddef.h>
38 #include <linux/unistd.h>
39 #include <linux/kallsyms.h>
40 #include <linux/uaccess.h>
41 #include <linux/rcupdate.h>
42 #include <linux/random.h>
43 #include <linux/nmi.h>
44
45 #include <asm/io.h>
46 #include <asm/asm-offsets.h>
47 #include <asm/assembly.h>
48 #include <asm/pdc.h>
49 #include <asm/pdc_chassis.h>
50 #include <asm/unwind.h>
51 #include <asm/sections.h>
52
53 #define COMMAND_GLOBAL F_EXTEND(0xfffe0030)
54 #define CMD_RESET 5 /* reset any module */
55
56 /*
57 ** The Wright Brothers and Gecko systems have a H/W problem
58 ** (Lasi...'nuf said) may cause a broadcast reset to lockup
59 ** the system. An HVERSION dependent PDC call was developed
60 ** to perform a "safe", platform specific broadcast reset instead
61 ** of kludging up all the code.
62 **
63 ** Older machines which do not implement PDC_BROADCAST_RESET will
64 ** return (with an error) and the regular broadcast reset can be
65 ** issued. Obviously, if the PDC does implement PDC_BROADCAST_RESET
66 ** the PDC call will not return (the system will be reset).
67 */
machine_restart(char * cmd)68 void machine_restart(char *cmd)
69 {
70 #ifdef FASTBOOT_SELFTEST_SUPPORT
71 /*
72 ** If user has modified the Firmware Selftest Bitmap,
73 ** run the tests specified in the bitmap after the
74 ** system is rebooted w/PDC_DO_RESET.
75 **
76 ** ftc_bitmap = 0x1AUL "Skip destructive memory tests"
77 **
78 ** Using "directed resets" at each processor with the MEM_TOC
79 ** vector cleared will also avoid running destructive
80 ** memory self tests. (Not implemented yet)
81 */
82 if (ftc_bitmap) {
83 pdc_do_firm_test_reset(ftc_bitmap);
84 }
85 #endif
86 /* set up a new led state on systems shipped with a LED State panel */
87 pdc_chassis_send_status(PDC_CHASSIS_DIRECT_SHUTDOWN);
88
89 /* "Normal" system reset */
90 pdc_do_reset();
91
92 /* Nope...box should reset with just CMD_RESET now */
93 gsc_writel(CMD_RESET, COMMAND_GLOBAL);
94
95 /* Wait for RESET to lay us to rest. */
96 while (1) ;
97
98 }
99
100 void (*chassis_power_off)(void);
101
102 /*
103 * This routine is called from sys_reboot to actually turn off the
104 * machine
105 */
machine_power_off(void)106 void machine_power_off(void)
107 {
108 /* If there is a registered power off handler, call it. */
109 if (chassis_power_off)
110 chassis_power_off();
111
112 /* Put the soft power button back under hardware control.
113 * If the user had already pressed the power button, the
114 * following call will immediately power off. */
115 pdc_soft_power_button(0);
116
117 pdc_chassis_send_status(PDC_CHASSIS_DIRECT_SHUTDOWN);
118
119 /* ipmi_poweroff may have been installed. */
120 if (pm_power_off)
121 pm_power_off();
122
123 /* It seems we have no way to power the system off via
124 * software. The user has to press the button himself. */
125
126 printk(KERN_EMERG "System shut down completed.\n"
127 "Please power this system off now.");
128
129 /* prevent soft lockup/stalled CPU messages for endless loop. */
130 rcu_sysrq_start();
131 lockup_detector_soft_poweroff();
132 for (;;);
133 }
134
135 void (*pm_power_off)(void);
136 EXPORT_SYMBOL(pm_power_off);
137
machine_halt(void)138 void machine_halt(void)
139 {
140 machine_power_off();
141 }
142
flush_thread(void)143 void flush_thread(void)
144 {
145 /* Only needs to handle fpu stuff or perf monitors.
146 ** REVISIT: several arches implement a "lazy fpu state".
147 */
148 }
149
release_thread(struct task_struct * dead_task)150 void release_thread(struct task_struct *dead_task)
151 {
152 }
153
154 /*
155 * Idle thread support
156 *
157 * Detect when running on QEMU with SeaBIOS PDC Firmware and let
158 * QEMU idle the host too.
159 */
160
161 int running_on_qemu __ro_after_init;
162 EXPORT_SYMBOL(running_on_qemu);
163
arch_cpu_idle_dead(void)164 void __cpuidle arch_cpu_idle_dead(void)
165 {
166 /* nop on real hardware, qemu will offline CPU. */
167 asm volatile("or %%r31,%%r31,%%r31\n":::);
168 }
169
arch_cpu_idle(void)170 void __cpuidle arch_cpu_idle(void)
171 {
172 raw_local_irq_enable();
173
174 /* nop on real hardware, qemu will idle sleep. */
175 asm volatile("or %%r10,%%r10,%%r10\n":::);
176 }
177
parisc_idle_init(void)178 static int __init parisc_idle_init(void)
179 {
180 if (!running_on_qemu)
181 cpu_idle_poll_ctrl(1);
182
183 return 0;
184 }
185 arch_initcall(parisc_idle_init);
186
187 /*
188 * Copy architecture-specific thread state
189 */
190 int
copy_thread(unsigned long clone_flags,unsigned long usp,unsigned long kthread_arg,struct task_struct * p,unsigned long tls)191 copy_thread(unsigned long clone_flags, unsigned long usp,
192 unsigned long kthread_arg, struct task_struct *p, unsigned long tls)
193 {
194 struct pt_regs *cregs = &(p->thread.regs);
195 void *stack = task_stack_page(p);
196
197 /* We have to use void * instead of a function pointer, because
198 * function pointers aren't a pointer to the function on 64-bit.
199 * Make them const so the compiler knows they live in .text */
200 extern void * const ret_from_kernel_thread;
201 extern void * const child_return;
202
203 if (unlikely(p->flags & (PF_KTHREAD | PF_IO_WORKER))) {
204 /* kernel thread */
205 memset(cregs, 0, sizeof(struct pt_regs));
206 if (!usp) /* idle thread */
207 return 0;
208 /* Must exit via ret_from_kernel_thread in order
209 * to call schedule_tail()
210 */
211 cregs->ksp = (unsigned long)stack + THREAD_SZ_ALGN + FRAME_SIZE;
212 cregs->kpc = (unsigned long) &ret_from_kernel_thread;
213 /*
214 * Copy function and argument to be called from
215 * ret_from_kernel_thread.
216 */
217 #ifdef CONFIG_64BIT
218 cregs->gr[27] = ((unsigned long *)usp)[3];
219 cregs->gr[26] = ((unsigned long *)usp)[2];
220 #else
221 cregs->gr[26] = usp;
222 #endif
223 cregs->gr[25] = kthread_arg;
224 } else {
225 /* user thread */
226 /* usp must be word aligned. This also prevents users from
227 * passing in the value 1 (which is the signal for a special
228 * return for a kernel thread) */
229 if (usp) {
230 usp = ALIGN(usp, 4);
231 if (likely(usp))
232 cregs->gr[30] = usp;
233 }
234 cregs->ksp = (unsigned long)stack + THREAD_SZ_ALGN + FRAME_SIZE;
235 cregs->kpc = (unsigned long) &child_return;
236
237 /* Setup thread TLS area */
238 if (clone_flags & CLONE_SETTLS)
239 cregs->cr27 = tls;
240 }
241
242 return 0;
243 }
244
245 unsigned long
get_wchan(struct task_struct * p)246 get_wchan(struct task_struct *p)
247 {
248 struct unwind_frame_info info;
249 unsigned long ip;
250 int count = 0;
251
252 if (!p || p == current || p->state == TASK_RUNNING)
253 return 0;
254
255 /*
256 * These bracket the sleeping functions..
257 */
258
259 unwind_frame_init_from_blocked_task(&info, p);
260 do {
261 if (unwind_once(&info) < 0)
262 return 0;
263 if (p->state == TASK_RUNNING)
264 return 0;
265 ip = info.ip;
266 if (!in_sched_functions(ip))
267 return ip;
268 } while (count++ < MAX_UNWIND_ENTRIES);
269 return 0;
270 }
271
272 #ifdef CONFIG_64BIT
dereference_function_descriptor(void * ptr)273 void *dereference_function_descriptor(void *ptr)
274 {
275 Elf64_Fdesc *desc = ptr;
276 void *p;
277
278 if (!get_kernel_nofault(p, (void *)&desc->addr))
279 ptr = p;
280 return ptr;
281 }
282
dereference_kernel_function_descriptor(void * ptr)283 void *dereference_kernel_function_descriptor(void *ptr)
284 {
285 if (ptr < (void *)__start_opd ||
286 ptr >= (void *)__end_opd)
287 return ptr;
288
289 return dereference_function_descriptor(ptr);
290 }
291 #endif
292
brk_rnd(void)293 static inline unsigned long brk_rnd(void)
294 {
295 return (get_random_int() & BRK_RND_MASK) << PAGE_SHIFT;
296 }
297
arch_randomize_brk(struct mm_struct * mm)298 unsigned long arch_randomize_brk(struct mm_struct *mm)
299 {
300 unsigned long ret = PAGE_ALIGN(mm->brk + brk_rnd());
301
302 if (ret < mm->brk)
303 return mm->brk;
304 return ret;
305 }
306